Hi Alex,
The screenshot clarifies the task. Lets assume that you have this data set:
DateTime (format is day/month/year) Value
1.2.2010 10
2.2.2010 11
1.3.2010 12
2.3.2010 13
1.2.2009 14
1.3.2009 15
We assume that you want to display a sum of the values for each distinct month in each year.
To do that you need to follow these steps:
1. Make a single Category grouping (not series grouping), with the following TWO group by expressions:
=MONTH(Fields!DateTime)
=YEAR(Fields!DateTime)
This is necessary, because if you simply group by month the records for January 2009 and January 2010 will be in the same group - e.g. each category group will actually contain data for a single month for all years.
2. Set the category label to be:
=MONTH(FIRST(Fields!DateTime))+"/"+YEAR(FIRST(Fields!DateTime))
This expression will display the Year/Month for the current group. Because all records in the group are having the same year and month you only need to get the first date time value in the group in order to make the category label.
3. Create a single values data grouping with Value expression set to:
=SUM(Fields!Value)
Assuming that you started with the default chart (e.g. either from a blank web part or by pressing the RESET button), this should create a bar chart with the following data:
Category Label Value
2/2010 21 (sum of records 1 and 2)
3/2010 25 (sum of records 3 and 4)
2/2009 14
3/2009 15
Best Regards,
Nevron Support Team